Electronic actuation module for elevator safety brake system

ABSTRACT

An electronic actuator for an elevator safety brake system, the actuator having: an electromagnet assembly; and a first magnet assembly configured for being retracted from engagement with a rail depending on an energized state of the electromagnet assembly, the first magnet assembly including: blocks spaced apart from each other, respectively defining block bodies, and elongated block legs respectively extending aft from the block bodies; and a first magnet is disposed between the block bodies; wherein the electromagnet assembly includes: a core that defines: a core body extending between core ends that are spaced apart from each other; and core stub legs respectively extending forward from the core ends that are positioned adjacent to the elongated block legs when the first magnet assembly is retracted; and a coil winding wound about bobbins that are placed over the core body, the elongated block legs are longer than the core stub legs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. Application No. 16/910,211 filedJun. 24, 2020, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND

The embodiments herein relate to elevator emergency brakes and morespecifically to an electronic Actuation Module for an elevator safetybrake system.

Safety regulations concerning the operation of elevators require anemergency brake (or safety brake) on the elevator car to stop theelevator in the event of an overspeed condition. The emergency brakeprogressively stops the vehicle by applying a frictional force to thehoistway rails guiding the vehicle. Cost effective and reliableemergency brakes are desired for all types of elevators, including highspeed elevators which may float relative to the hoistway rail more thanlow speed elevators and thus have relatively large airgaps.

BRIEF SUMMARY

An electronic actuator for an elevator safety brake system, the actuatorhaving: an electromagnet assembly; and a first magnet assemblyconfigured for being retracted from engagement with a hoistway raildepending on an energized state of the electromagnet assembly, whereinthe first magnet assembly includes: blocks spaced apart from each otherin a transverse direction, respectively defining block bodies, andelongated block legs respectively extending aft from the block bodies;and a first magnet is disposed transversely between the block bodies;wherein the electromagnet assembly includes: a core that defines: a corebody extending between core ends that are transversely spaced apart fromeach other; and core stub legs respectively extending forward from thecore ends that are positioned adjacent to the elongated block legs whenthe first magnet assembly is retracted; and a coil winding wound aboutbobbins that are placed over the core body, wherein the elongated blocklegs are longer in a forward-aft direction than the core stub legs.

In addition to one or more aspects for the actuator, or as an alternate,the coil winding defines a coil winding thickness in the forward-aftdirection and the core stub legs define a stub leg length in theforward-aft direction, wherein the stub leg length is less than 50% ofthe coil winding thickness.

In addition to one or more aspects for the actuator, or as an alternate,the stub leg length is less than 15% of the coil winding thickness.

In addition to one or more aspects for the actuator, or as an alternate,the elongated block legs and the core stub legs are configured so thatwhen the first magnet assembly is retracted, the first magnet and thecoil winding are spaced apart from each other in the forward-aftdirection by a first clearance gap distance to define a first clearancegap therebetween.

In addition to one or more aspects for the actuator, or as an alternate,the actuator has a system housing that defines a hoistway railengagement aperture wherein: the electromagnet assembly is disposedwithin the system housing, spaced apart from the hoistway railengagement aperture; the first magnet assembly is disposed in the systemhousing between the electromagnet assembly and the hoistway railengagement aperture, the first magnet assembly configured for beingretracted into the system housing from engagement with the hoistway railvia the hoistway rail engagement aperture, when the electromagnetassembly, depending on its energized state, moves to engage the firstmagnet assembly; and a return biasing member is disposed between thesystem housing and the electromagnet assembly to bias into the systemhousing the electromagnet assembly and the first magnet assembly, whichare stuck to each other via magnetism.

Further disclosed is a method of operating an electronic actuator of anelevator safety brake, the method having: energizing an electromagnetassembly of the electronic actuator, which attracts an electromagnetassembly of the electronic actuator to the magnet assembly; theelectromagnet assembly moving forward, to engage an aft side of themagnet assembly, against the biasing of a return biasing member of theelectronic actuator; elongated block legs of the first magnet assemblyand core stub legs of the electromagnet assembly engaging each otherfrom movement of the electromagnet assembly; and retracting, by biasingfrom the return biasing member, the first magnet assembly and theelectromagnet assembly, which are magnetically stuck together.

In addition to one or more aspects for the method, or as an alternate, acoil winding of the electromagnet assembly defines a coil windingthickness in the forward-aft direction and the core stub legs define astub leg length in the forward-aft direction, wherein the stub leglength is less than 50% of the coil winding thickness.

In addition to one or more aspects for the method, or as an alternate,wherein the stub leg length is less than 15% of the coil windingthickness.

In addition to one or more aspects for the method, or as an alternate,the elongated block legs and the core stub legs are configured so thatwhen the first magnet assembly is retracted, the first magnet and thecoil winding are spaced apart from each other in the forward-aftdirection by a first clearance gap distance to define a first clearancegap therebetween.

In addition to one or more aspects for the method, or as an alternate,the electronic actuator includes a system housing that defines ahoistway rail engagement aperture, wherein: the electromagnet assemblyis disposed within the system housing, spaced apart from the hoistwayrail engagement aperture; the first magnet assembly is disposed in thesystem housing between the electromagnet assembly and the hoistway railengagement aperture; and the return biasing member is disposed betweenthe system housing and the electromagnet assembly, and the methodincludes: retracting the first magnet assembly and the electromagnetassembly, which are magnetically stuck together, into the system housingby biasing from the return biasing member.

Further disclosed is an electronic actuator for an elevator safetybrake, having: an electromagnet assembly; and a first magnet assemblydisposed forward of the electromagnet assembly and configured for beingdeployed to engage, and retracted from engagement with, a hoistway rail,depending on an energized sate of the electromagnet assembly, and asecond magnet assembly disposed aft of the electromagnet assembly,wherein the first and second magnet assemblies are configured with areverse polarity relative to each other.

In addition to one or more aspects for the actuator, or as an alternate,the first magnet assembly includes: blocks spaced apart from each otherin a transverse direction, respectively defining block bodies, and blocklegs respectively extending aft from the block bodies; and the firstmagnet is disposed transversely between the block bodies; and the secondmagnet assembly includes: further blocks spaced apart from each other inthe transverse direction, respectively defining further block bodies,and further block legs respectively extending forward from the furtherblock bodies; and the second magnet is disposed transversely between thefurther block bodies.

In addition to one or more aspects for the actuator, or as an alternate,the electromagnet assembly has a core that is H-shaped to define legsthat respectively engage the first through fourth block legs when thefirst magnet assembly and the electromagnet assembly are retracted.

In addition to one or more aspects for the actuator, or as an alternate,the core that defines: a core body extending between core ends that aretransversely spaced apart from each other; core legs respectivelyextending forward from the core ends, to respectively engage the blocklegs; further core legs respectively extending aft from the core ends,to respectively engage the further block legs; a coil winding is woundabout bobbins placed about the core body; and when the first magnetassembly and the electromagnet assembly are retracted, the first magnetand the coil winding are spaced apart from each other in a forward-aftdirection by a first clearance gap distance to define a first clearancegap therebetween, and the second magnet and the coil winding are spacedapart from each other in the forward-aft direction by a second clearancegap distance to define a second clearance gap therebetween.

In addition to one or more aspects for the actuator, or as an alternate,the actuator includes a system housing that defines a hoistway railengagement aperture, wherein: the electromagnet assembly is disposedwithin the system housing, spaced apart from the hoistway railengagement aperture; the first magnet assembly is disposed in the systemhousing between the electromagnet assembly and the hoistway railengagement aperture; the second magnet assembly is disposed in thesystem housing so that the electromagnet assembly is between the secondmagnet assembly and the hoistway rail engagement aperture; and thereturn biasing member is disposed between the system housing and theelectromagnet assembly.

Further disclosed is a method of operating an electronic actuator of anelevator safety brake, the method having: a first magnet assembly of theelectronic actuator, being magnetically attracted to an electromagnetassembly of the electronic actuator; return biasing member, of theelectronic actuator, acting to retain the first magnet assembly; asecond magnet assembly of the electronic actuator acting to retain thefirst magnet assembly due to magnetic attraction with the electromagnetassembly; energizing the electromagnet assembly to repel the firstmagnet assembly, moving it to the rail, and thereby increasing magneticattraction of the electromagnet assembly to the first magnet assembly;energizing the electromagnet assembly to reverse its polarity, causingthe electromagnet assembly to simultaneously be attracted to the firstmagnet assembly and be repelled from the second magnet assembly; theelectromagnet assembly moving to contact the first magnet assembly frommagnetic attraction therebetween; and the return biasing member biasingthe electromagnet assembly moving to contact the first magnet assembly,stuck to each other by magnetism, back into the system housing

In addition to one or more aspects for the method, or as an alternate,the first magnet assembly includes: blocks spaced apart from each otherin a transverse direction, respectively defining block bodies, and blocklegs respectively extending aft from the block bodies; and the firstmagnet is disposed transversely between the block bodies; and the secondmagnet assembly includes: further blocks spaced apart from each other inthe transverse direction, respectively defining further block bodies,and further block legs respectively extending forward from the furtherblock bodies; and the second magnet is disposed transversely between thefurther block bodies.

In addition to one or more aspects for the method, or as an alternate,the electromagnet assembly has a core that is H-shaped to define legsthat respectively engage the first through fourth block legs when thefirst magnet assembly and the electromagnet assembly are retracted.

In addition to one or more aspects for the method, or as an alternate,the core that defines: a core body extending between core ends that aretransversely spaced apart from each other; core legs respectivelyextending forward from the core ends, to respectively engage the blocklegs; further core legs respectively extending aft from the core ends,to respectively engage the further block legs; a coil winding is woundabout bobbins placed about the core body; and when the first magnetassembly and the electromagnet assembly are retracted, the first magnetand the coil winding are spaced apart from each other in a forward-aftdirection by a first clearance gap distance to define a first clearancegap therebetween, and the second magnet and the coil winding are spacedapart from each other in the forward-aft direction by a second clearancegap distance to define a second clearance gap therebetween.

In addition to one or more aspects for the method, or as an alternate,the electronic actuator includes a system housing that defines ahoistway rail engagement aperture, wherein: the electromagnet assemblyis disposed within the system housing, spaced apart from the hoistwayrail engagement aperture; the first magnet assembly is disposed in thesystem housing between the electromagnet assembly and the hoistway railengagement aperture; the second magnet assembly is disposed in thesystem housing so that the electromagnet assembly is between the secondmagnet assembly and the hoistway rail engagement aperture; and thereturn biasing member is disposed between the system housing and theelectromagnet assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of example and not limitedin the accompanying figures in which like reference numerals indicatesimilar elements.

FIG. 1A is a schematic illustration of an elevator system that mayemploy various embodiments of the present disclosure;

FIG. 1B is an example arrangement of an overspeed safety system forelevators;

FIG. 1C is an isometric illustration of an elevator car frame having anoverspeed safety system in accordance with an embodiment of the presentdisclosure;

FIG. 1D is an enlarged illustrative view of a portion of the overspeedsafety system of FIG. 1C;

FIG. 2A is an example electronic actuator or Force Actuation Module(FAM) for an elevator brake system connected to a safety mechanism ofthe elevator brake system;

FIG. 2B is the FAM shown in FIG. 2A;

FIG. 3A is the FAM of FIG. 2B along view lines 3-3;

FIG. 3B is the FAM of FIG. 3A with the system housing removed;

FIG. 3C is the FAM of FIG. 3B with the permanent magnet assembly housingremoved and the electromagnetic assembly housing removed;

FIG. 4A is the FAM of FIG. 3 along view lines 4-4;

FIG. 4B is the FAM of FIG. 4A with the permanent magnet assembly housingremoved and the electromagnetic assembly housing removed;

FIG. 5 is a top schematic view of the FAM of FIG. 4 ;

FIG. 6A is a top schematic view of a FAM according to an embodiment;

FIG. 6B is a top view of an elevator car equipped with left and rightFAMs according to an embodiment;

FIG. 7 is another top schematic view of the FAM of FIG. 6 , where afirst permanent magnet assembly of the FAM has engaged a hoistway rail;

FIG. 8 is another top schematic view of the FAM of FIG. 7 , where thefirst permanent magnet assembly of the FAM is in the process of beingretracted back by an electromagnet assembly of the FAM;

FIG. 9 is a flowchart showing a method of operating the FAM of FIG. 6 ;

FIG. 10 is a top schematic view of a FAM according to anotherembodiment;

FIG. 11 is another top schematic view of the FAM of FIG. 9 , where afirst permanent magnet assembly of the FAM is being deployed to engagethe hoistway rail;

FIG. 12 is another top schematic view of the FAM of FIG. 9 , where anelectromagnet assembly of the FAM is deployed to engage the firstpermanent magnet assembly from repulsive interactions with a secondpermanent magnet assembly of the FAM, where the second permanent magnetassembly remains in a stationary position;

FIG. 13 is another top schematic view of the FAM of FIG. 9 , where theelectromagnet assembly has engaged the first permanent magnet assemblyto retract the first permanent magnet assembly from the hoistway rail;and

FIG. 14 is a flowchart showing a method of operating the FAM of FIG. 10.

DETAILED DESCRIPTION

FIG. 1A is a perspective view of an elevator system 101 including anelevator car 103, a counterweight 105, a tension member 107, a hoistway(or guide) rail 109, a machine 111, a position reference system 113, anda controller 115. The elevator car 103 and counterweight 105 areconnected to each other by the tension member 107. The tension member107 may include or be configured as, for example, ropes, steel cables,and/or coated-steel belts. The counterweight 105 is configured tobalance a load of the elevator car 103 and is configured to facilitatemovement of the elevator car 103 concurrently and in an oppositedirection with respect to the counterweight 105 within an elevator shaft117 and along the hoistway rail 109.

The tension member 107 engages the machine 111, which is part of anoverhead structure of the elevator system 101. The machine 111 isconfigured to control movement between the elevator car 103 and thecounterweight 105. The position reference system 113 may be mounted on afixed part at the top of the elevator shaft 117, such as on a support orguide hoistway rail, and may be configured to provide position signalsrelated to a position of the elevator car 103 within the elevator shaft117. In other embodiments, the position reference system 113 may bedirectly mounted to a moving component of the machine 111, or may belocated in other positions and/or configurations as known in the art.The position reference system 113 can be any device or mechanism formonitoring a position of an elevator car and/or counter weight, as knownin the art. For example, without limitation, the position referencesystem 113 can be an encoder, sensor, or other system and can includevelocity sensing, absolute position sensing, etc., as will beappreciated by those of skill in the art.

The controller 115 is located, as shown, in a controller room 121 of theelevator shaft 117 and is configured to control the operation of theelevator system 101, and particularly the elevator car 103. For example,the controller 115 may provide drive signals to the machine 111 tocontrol the acceleration, deceleration, leveling, stopping, etc. of theelevator car 103. The controller 115 may also be configured to receiveposition signals from the position reference system 113 or any otherdesired position reference device. When moving up or down within theelevator shaft 117 along hoistway rail 109, the elevator car 103 maystop at one or more landings 125 as controlled by the controller 115.Although shown in a controller room 121, those of skill in the art willappreciate that the controller 115 can be located and/or configured inother locations or positions within the elevator system 101. In oneembodiment, the controller may be located remotely or in the cloud.

The machine 111 may include a motor or similar driving mechanism. Inaccordance with embodiments of the disclosure, the machine 111 isconfigured to include an electrically driven motor. The power supply forthe motor may be any power source, including a power grid, which, incombination with other components, is supplied to the motor. The machine111 may include a traction sheave that imparts force to tension member107 to move the elevator car 103 within elevator shaft 117.

Although shown and described with a roping system including tensionmember 107, elevator systems that employ other methods and mechanisms ofmoving an elevator car within an elevator shaft may employ embodimentsof the present disclosure. For example, embodiments may be employed inropeless elevator systems using a linear motor to impart motion to anelevator car. Embodiments may also be employed in ropeless elevatorsystems using a hydraulic lift to impart motion to an elevator car. FIG.1 is merely a non-limiting example presented for illustrative andexplanatory purposes.

Turning to FIG. 1B, a schematic illustration of an example elevator caroverspeed safety system 127 of the elevator system 101 is shown. Theelevator system 101 includes the elevator car 103 that is movable withinthe elevator shaft along guide rails 109. In this illustrativeembodiment, the overspeed safety system 127 includes a pair of brakingelements 129 that are engageable with the guide rails 109. The brakingelements 129 are actuated, in part, by operation of lift rods 131. Thetriggering of the braking elements 129 is achieved through elevatorgovernor 133, typically located at the top of the elevator shaft, whichincludes a tension device 135 located within the pit of the elevatorshaft with a cable 137 operably connecting the governor 133 and thetension device 135. When an overspeed event is detected by the governor,the overspeed safety system 127 is triggered, and a linkage 139 isoperated to actuate a combination of lift rods 131 simultaneously tocause actuation (e.g., self-engagement) of the braking elements 129(e.g., safety wedges) that engage with the guide rail and cause a smoothand even stopping or braking force to stop the travel of the elevatorcar. As used herein the term “overspeed event” refers to an event duringwhich a speed, velocity, or acceleration of an elevator car exceeds apredetermined threshold of the respective state of motion, and is notintended to be limited to constant speed, but rather also includes ratesof change (e.g., acceleration) and also direction of travel of motionthe elevator car (e.g., velocity). The linkage 139, as shown, is locatedon the top of the elevator car 103 and ensures simultaneous operation ofthe braking elements 129. However, in other configurations, the linkagemay be located below a platform (or bottom) of the elevator car. Asshown, various components are located above and/or below the elevatorcar 103, and thus pit space and overhead space within the elevator shaftmust be provided to permit operation of the elevator system 101.

Turning now to FIGS. 1C-1D, schematic illustrations of an elevator car303 having an overspeed safety system 300 in accordance with anembodiment of the present disclosure are shown. FIG. 1C is an isometricillustration of an elevator car frame 304 with the overspeed safetysystem 300 installed thereto. FIG. 1D is an enlarged illustration of aportion of the overspeed safety system 300 showing a relationship with aguide rail.

The car frame 304 includes a platform 306, a ceiling 308, a first carstructural member 310, and a second car structural member 312. The carframe 304 defines a frame for supporting various panels and othercomponents that define the elevator car for passenger or other use(i.e., define a cab of the elevator), although such panels and othercomponents are omitted for clarity of illustration. The elevator car 303is moveable along guide rails 309 (shown in FIG. 1D), similar to thatshown and described above. The overspeed safety system 300 provides asafety braking system that can stop the travel of the elevator car 303during an overspeed event.

The overspeed safety system 300 includes a first safety brake 314, afirst electromechanical actuator 316 (or actuator 316) connected to itby a connecting rod 332, and a controller or control system 318 operablyconnected to the first electromechanical actuator 316. In oneembodiment, the actuator 316 may include safety wedges typically foundin a safety brake, such as the first safety brake 314, and is sized toproduce sufficient braking forces so as to function as a safety brake.

The first safety brake 314 and the first electromechanical actuator 316are arranged along the first car structural member 310. A second safetybrake 320 and a second electromechanical actuator 322 are arranged alongthe second car structural member 312. The control system 318 is alsooperably connected to the second electromechanical actuator 322. Theconnection between the control system 318 and the electromechanicalactuators 316, 322 may be provided by a communication line 324. Thecommunication line 324 may be wired or wireless, or a combinationthereof (e.g., for redundancy). The communication line 324 may be anelectrical wire to supply electrical power from the control system 318and an electromagnet of the first electromechanical actuator 316. Itwill be appreciated that in alternative configurations, thecommunication may be a wireless communication system, both fordata/information and/or wireless power transfer.

As shown, the control system 318 is located on the top or ceiling 308 ofthe car frame 304. However, such position is not to be limiting, and thecontrol system 318 may be located anywhere within the elevator system(e.g., on or in the elevator car, within a controller room, etc.). Thecontrol system 318 may comprise electronics and printed circuit boardsfor processing (e.g., processor, memory, communication elements,electrical buss, etc.). Thus, the control system 318 may have a very lowprofile and may be installed within ceiling panels, wall panels, or evenwithin a car operating panel of the elevator car 303. In otherconfigurations, the control system 318 may be integrated into various ofthe components of the overspeed safety system 300 (e.g., within or partof the electromechanical actuator 316).

The overspeed safety system 300 is an electromechanical system thateliminates the need for a linkage or linking element installed at thetop or bottom of the elevator car. That is, the system 300 may replace atraditional governor system, including a governor, a governor rope andgovernor tension devices.

The control system 318 may include, for example, a printed circuit boardwith multiple inputs and outputs. In some embodiments, the controlsystem 318 may include circuitry for a system for control, protection,and/or monitoring based on one or more programmable electronic devices(e.g., power supplies, sensors, and other input devices, data highwaysand other communication paths, and actuators and other output devices,etc.). The control system 318 may further include various components toenable control in the event of a power outage (e.g., capacitor/battery,etc.). The control system 318 may also include an accelerometer or othercomponent/device to determine a speed of an elevator car (e.g., opticalsensors, laser range finders, etc.). In such embodiments, the controlsystem 318 is mounted to the elevator car, as shown in the illustrativeembodiments herein.

The control system 318, in some embodiments, may be connected to and/orin communication with a car positioning system, an accelerometer mountedto the car (i.e., a second or separate accelerometer), and/or to theelevator controller. Accordingly, the control system 318 may obtainmovement information (e.g., speed, direction, acceleration) related tomovement of the elevator car along an elevator shaft. The control system318 may operate independently of other systems, other than potentiallyreceiving movement information, to provide a safety feature to preventoverspeed events.

The control system 318 may process the movement information provided bya car positioning system to determine if an elevator car is traveling ata speed in excess of a threshold speed. If the threshold is exceeded,the control system 318 will trigger the electromechanical actuators andthe safety brakes. The control system 318 will also provide feedback tothe elevator control system about the status of the overspeed safetysystem 300 (e.g., normal operational position/triggered position). Itwill be appreciated that although referred to as an “overspeed” system,the systems may be configured to determine if an elevator car isaccelerating at a rate in excess of a threshold acceleration, and theterm “overspeed” is not to be limiting to merely a constant rate ofmotion.

Thus, the overspeed safety system 300 of the present disclosure enableselectrical and electromechanical safety braking in the event ofoverspeed conditions or events. The electrical aspects of the presentdisclosure enable the elimination of the physical/mechanical linkagesthat have traditionally been employed in overspeed safety systems. Thatis, the electrical connections allow for simultaneous triggering of twoseparate safety brakes through electrical signals, rather than relyingupon mechanical connections and other components such as wheels, ropes,etc.

For additional illustrative context, FIGS. 2-5 will be addressed. FIG.2A shows an example Force Actuation Module (FAM) 200, which is anelectronic (or electromechanical) actuator (similar to theelectromechanical actuator 316 disclosed above). The FAM 200 isconnected by a safety linkage 201 a (similar to the connecting rod 332disclosed above) to a safety mechanism 201 b (similar to the firstsafety brake 314 disclosed above). The FAM 200 provides the liftingforce necessary to actuate the elevator safety mechanism 201 b, which isone of the functions of the governor. That is, the FAM 200 generates aforce that results in lifting of the safety wedges from the first safetybrake 314, which is otherwise a function of the governor.

The elevator safety mechanism 201 c then provides the braking force tobring an elevator to a stop in an emergency (e.g. runaway or freefall).A permanent magnet assembly 210 of the FAM 200 is deployed to the rail109, magnetically sticks to the rail 109, and lifts the attached safetywedge or wedges 201 c of the safety mechanism 201 b. The safetymechanism 201 b then brings the elevator car 103 to a stop. Thepermanent magnet assembly 210 of each FAM (one FAM 210A1 on a left side226 a of the elevator car 103 (FIG. 6B) and one FAM 210A2 on a rightside 226B of the elevator car 103 (FIG. 6B)) is triggered at or above anoverspeed threshold (in one non-limiting example, during runaway orfreefall) and would do so if removing power from a motor or brake of themachine 111 (FIG. 1 ) proved ineffective in decelerating the elevatorcar 103.

The safety mechanism 201 b is located below the FAM 200. The safetylinkage connects a permanent magnet assembly 210 (discussed in greaterdetail below) of the FAM 200 to the safety wedge or wedges 201 c of thesafety mechanism 201 b. The safety mechanism 201 b could also be locatedabove the FAM 200.

As shown in FIGS. 2B, 3A-3C and 4A, 4B the FAM 200 includes a systemhousing 202 (not shown in FIGS. 3B, 3C and 4B) with a housing forwardside 204 and a housing aft side 206 spaced apart from one another in aforward-aft direction 208. A permanent magnet assembly 210 (or firstmagnet assembly) is disposed in the system housing forward side 204 ofthe system housing 202 and electromagnet assembly 212 is disposed aft ofthe permanent magnet assembly 210. The permanent magnet assembly 210 isdisposed in a permanent magnet assembly housing 211 (not shown in FIGS.3C and 4B) to maintain a configuration of components therein. Anelectromagnet assembly 212 is disposed in an electromagnet assemblyhousing 213 (not shown in FIGS. 3C and 4B) to maintain a configurationof components therein. Return biasing features 214, 216 (FIG. 3A) aredisposed between the electromagnet assembly housing 213 and the systemhousing 202 to keep the electromagnet assembly housing 213 within thesystem housing 202 during operation.

In the illustrated embodiment the return biasing features 214, 216 arereturn springs connecting the electromagnet assembly 212B to the housing202. In one embodiment, rather than return springs 214, 216, the returnbiasing members 214, 216 that bias the electromagnet assembly 212B toremain in the housing 202 may include, for example, implements (e.g.,one or more pumps) that provide pneumatic or hydraulic pressure, or theutilization of elastomers or rubber springs. Leads 218 provide power tothe electromagnet assembly 212. When engaging a hoistway rail 109 (FIG.5 ) at least a portion of the permanent magnet assembly 210 travelsthrough a hoistway rail engagement aperture 220 defined in the systemhousing forward side 204 of the system housing 202.

As shown in FIGS. 3C, 4B and 5 , the permanent magnet assembly 210includes first and second blocks 222, 224, which may be made of steel,spaced apart from each other in a transverse direction 226, which isnormal to the forward-aft direction 208, respectively defining first andsecond block bodies 228, 230 (FIG. 5 , outlined by respective dashedboxes). First and second block teeth 232, 234 (FIG. 5 , outlined byrespective dashed boxes) respectively extend forward from the first andsecond block bodies 228, 230. First and second block legs 236, 238 (FIG.5 , outlined by respective dashed boxes) respectively extend aft fromthe first and second block bodies 228, 230. A first permanent magnet 240(first magnet) is disposed transversely between the first and secondblock bodies 228, 230.

The electromagnet assembly includes a core 242, which may be laminatedsteel, that defines a core body 244 (FIG. 5 , outlined by a dashed box)between transversely spaced apart first and second core ends 246, 248(FIG. 5 , outlined by respective dashed boxes). First and second corelegs 250, 252 (FIG. 5 , outlined by respective dashed boxes)respectively extend forward from the first and second core ends 246,248, to respectively engage the first and second block legs 236, 238. Acoil winding 254 is wound about top and bottom bobbins 255A, 255B (FIGS.3C, 4B) positioned against the core body 244.

As show in FIG. 5 , the first and second core legs 250, 252 have alength in the forward-aft direction 208 that is equivalent to athickness of the coil winding 254 in the forward-aft direction. As shownin greater details below, reducing the length of the first and secondcore legs 250, 252, may result in a more efficient utilization ofmagnetic flux for retracting the permanent magnet assembly 210 that isdeployed against the hoistway rail 109.

Turning to FIGS. 6-9 , according to an embodiment, a FAM 200A is shownfor the elevator system 101. Features in FIGS. 2-5 not addressed inFIGS. 6-9 , including the system housing 202, the permanent magnetassembly housing 211, the electromagnet assembly housing 213 and thereturn biasing members 214, 216, are considered the same as those inFIGS. 2-5 .

Turning to FIG. 6A, the FAM 200A includes an electromagnet assembly212A. A first permanent magnet assembly 210A (or first magnet assembly)is configured for being retracted from engagement with the hoistway rail109 when the electromagnet assembly 212A is an active energized state(i.e., when it is energized). The first permanent magnet assembly 210Aincludes first and second blocks 222A, 224A, spaced apart from eachother in the transverse direction 226, respectively defining first andsecond block bodies 228A, 230A (outlined by respective dashed boxes).First and second block teeth 232A, 234A (outlined by respective dashedboxes) respectively extend forward from the first and second blockbodies 228A, 230A, relative to the forward-aft direction 208. With thisconfiguration, the permanent magnet assembly 210A has a frictioninterface. This friction interface may be in the form of a series ofteeth. However, in one embodiment, there are other options for creatinga friction interface, including an application of a super abrasivecoating to a flat, toothless surface.

First and second elongated block legs 236A, 238A (outlined by respectivedashed boxes) respectively extending aft from the first and second blockbodies 228A, 230A. The first permanent magnet 240A is disposedtransversely between the first and second block bodies 228A, 230A.

The electromagnet assembly 212A includes a core 242A that defines a corebody 244A (outlined by a dashed box) extending between transverselyspaced apart first and second core ends 246A, 248A (outlined byrespective dashed boxes). First and second core stub legs 250A, 252A(outlined by respective dashed boxes) respectively extending forwardfrom the first and second core ends 246A, 248A to engage (or bepositioned adjacent to, in the forward-aft direction) the first andsecond elongated block legs 236A, 238A when the first permanent magnetassembly 210A is retracted. A coil winding 254A is wound about the corebody 244A. The first and second elongated block legs 236A, 238A arelonger in the forward-aft direction 208 than the first and second corestub legs 250A, 252A.

According to an embodiment, the winding 254A defines a coil windingthickness BT in the forward-aft direction 208 and the first and secondcore stub legs 250A, 252A define a stub leg length SL in the forward-aftdirection 208. The stub leg length SL may be less than 50% of the coilwinding thickness BT. The stub leg length SL may be also be more than orequal to 50% of the coil winding thickness BT. In one embodiment,wherein the stub leg length SL is less than 15% of the coil windingthickness BT. Thus, the core 242A may be rectangularly shaped.

The first and second elongated block legs 236A, 238A and the first andsecond core stub legs 250A, 252A are configured so that when the firstpermanent magnet assembly 210A is retracted, the first permanent magnet240A and the coil winding 254A are spaced apart from each other in theforward-aft direction 208 by a first clearance gap distance G1 to definea first clearance gap therebetween. It would be undesirable for thepermanent magnet 240 a to collide with the core 242A during reset.Therefore, some clearance is required. In practice, this clearance mightbe quite minimal. Another gap is an air gap AG between the teeth 232A,234A and the rail 109 when the permanent magnet assembly 210A is in aretracted state.

FIG. 6B shows the elevator 103 and rails 109 a, 109 b (generally rail109 in the remainder of this disclosure) in a top view. The figure showsthe forward-aft axis 208, e.g., between front and back sides 208 a, 208b of the elevator car 103, with elevator doors 103A at the front side208 a. The figure also shows the transvers axis 226, e.g., between theleft to right sides 226 a, 226 b of the elevator car 103.

A top view of left and right FAMs 210A1, 210A2 (generally 210A) areshown with the air gap AG identified relative to the left FAM 210A1. Theair gap AG may increase with elevator speed. As the elevator travels upand down within the hoistway, the car 103 may float in the forward-aftdirection due to imperfections in rail alignment, installation,passenger motion, etc. In higher speed elevators this front-to-back airgap AG tends to be larger. This allows for a smoother ride. Limiting thefront-to-back air gap AG, or traveling at faster speeds, may have theeffect of deteriorating the ride quality, e.g., making the ride bumpier,for the passengers.

Turning to FIG. 7 , three magnetic fields F1, F2, F3 that are presentduring the resetting of the FAM 200A are shown. The first field F1,which is a permanent magnetic-to-hoistway rail field, travelsdirectionally out of the first permanent magnet 240A, through thehoistway rail 109, and back in to the first permanent magnet 240A. Thisfirst field F1 attracts the first permanent magnet assembly 210B to thehoistway rail 109 during an emergency stop. The second field F2 is aleakage flux, which begins and ends within the electromagnet assembly212, traverses around the coil winding 254A and does not go through thepermanent magnet assembly 210B. The second field F2, generated whenretracting the first permanent magnet assembly 210A, does not assist inretracting the first permanent magnet assembly 210A. The third field F3,an electromagnet-to-permanent magnet field, travels directionally out ofthe core 242A, into the first permanent magnet 240A, out of the firstpermanent magnet 240A and into the core 242A. The third field F3 isuseful in retracting the permanent magnet.

As shown in FIG. 8 , the minimized length of each of the first andsecond core stub legs 250A, 252A, minimizes the effect of the secondfield F2, i.e., the electromagnet-to-winding field, by requiring it totravel through an amount of air (as shown by solid arrow A1). Increasingthe distance A1 increases the magnetic reluctance of this magnetic loop,thereby reducing the related magnetic flux via the second field F2. Thetotal available magnetic flux for creating the third field F3, i.e., theelectromagnet-to-permanent magnet field, is increased. As a result, theFAM 200A will be more efficient and effective at resetting over largerairgaps that may exist between the core 242A and first permanent magnet240A when the first permanent magnet 240A has engaged the elevatorhoistway rail 109.

FIG. 9 shows a method of operating an elevator system 101 equipped withthe FAM of FIGS. 6-8 . As shown in block 900, the method includesenergizing the electromagnet assembly 212A of the electronic actuator200 of the elevator governor. As a result, Field F3 is created, whichattracts the electromagnet assembly 212A to the permanent magnetassembly 210A. As shown in block 905 the method includes theelectromagnet assembly 212A moving forward, towards an aft side ofpermanent magnet assembly 210A, against the force of the return biasingmembers 214, 216. As shown in block 905 the method includes theelectromagnet assembly 212A moving forward, to engage an aft side of thepermanent magnet assembly 210A. As shown in block 910 the methodincludes the first and second elongated block legs 236A, 238A of thefirst permanent magnet assembly 210A and the first and second core stublegs 236A, 238A of the electromagnet assembly 212A engaging each otherfrom movement of the electromagnet assembly.

As shown in block 920 the method includes the presence of theelectromagnet assembly on the back of the magnet assembly 210A (and thecurrent that might still be flowing through the coil windings 224 of theelectromagnet assembly 212) reducing the attraction of the permanentmagnet assembly 210A toward the rail 109. As shown in block 930, themethod includes retracting, by force of the return biasing members 214,216, the first permanent magnet assembly 210A and the electromagnetassembly 212A, which are magnetically stuck together, into the systemhousing 202.

The above disclosed embodiments pertain to a cost-effective design of aForce Actuation Module (FAM), which is an electronic actuator, and whichmay constitute part of an elevator governor subsystem that is able toreset over large airgaps. This may be advantageous for higher speedelevators where larger airgaps are present due to the increasedfront-to-back float. The core of the electromagnet assembly is I(capital i) shaped (or truncated C shaped), and the first magnetassembly has relatively long legs. An implementation of these featuresenables the core to be more effective during reset because the amount ofleakage flux is significantly reduced.

Turning to FIGS. 10-14 , according to another embodiment, a FAM 200B isshown for the elevator system 101. Features in FIGS. 2-5 not addressedin FIGS. 10-14 , including the system housing 202, the permanent magnetassembly housing 211, the electromagnet assembly housing 213 and thereturn biasing members 214, 216, are considered the same as those inFIGS. 2-5 . The FAM 200A is utilized with the safety mechanism 210B(FIG. 2A), which may be located below the FAM 200A, and the safetylinkage 201A that connects the permanent magnet assembly of the FAM 200Bto the safety mechanism 201 b (see FIG. 2A). The safety mechanism 201Bcould also be located above the FAM 200B.

As shown in FIG. 10 , a FAM 200B is shown for the elevator system 101.The FAM 200B includes an electromagnet assembly 212B. A first permanentmagnet assembly 210B (or first magnet assembly) is disposed forward ofthe electromagnet assembly 212B, relative to the forward-aft direction208. The first permanent magnet assembly 210B is configured for beingdeployed to engage, and retracted from engagement with, a hoistway rail109, when the electromagnet assembly 212 is energized. A secondpermanent magnet assembly 210C (or second magnet assembly) is disposedaft of the electromagnet assembly 212B. The second permanent magnetassembly 210C is configured to attract the electromagnet assembly whendeploying the first permanent magnet assembly 210B and to repel theelectromagnet assembly 212B when retracting the first permanent magnetassembly 210B.

The first permanent magnet assembly 210B includes a first permanentmagnet 240B (or first magnet). The second permanent magnet assembly 210Cincludes a second permanent magnet 240C (or second magnet). The polarityof the first and second permanent magnet assemblies 210B, 240B arereversed with respect to each other. More specifically, the firstpermanent magnet assembly 210B includes first and second blocks 222B,224B spaced apart from each other in the transverse direction 226,respectively defining first and second block bodies 228B, 230B (outlinedby respective dashed boxes). First and second block teeth 232B, 234B(outlined by respective dashed boxes) respectively extend forward fromthe first and second block bodies 228B, 230B. With this configuration,as indicated above, the permanent magnet assembly 210A has a frictioninterface. This friction interface may be in the form of a series ofteeth. However, in one embodiment, there are other options for creatinga friction interface, including an application of a super abrasivecoating to a flat, toothless surface.

First and second block legs 236B, 238B (outlined by respective dashedboxes) respectively extending aft from the first and second block bodies228B, 230B. The first permanent magnet 240B is disposed transverselybetween the first and second block bodies 228B, 230B.

The second permanent magnet assembly 210C includes third and fourth(further) blocks 222, 224 spaced apart from each other in the transversedirection 226, respectively defining third and fourth (further) blockbodies 228C, 230C (outlined by respective dashed boxes). Third andfourth (further) block legs 236C, 238C (outlined by respective dashedboxes) respectively extend forward from the third and fourth blockbodies 228C, 230C. The second permanent magnet 240C is disposedtransversely between the third and fourth block bodies 228C, 230C. Theelectromagnet assembly 212B has a core 242B that is H-shaped to definelegs 250B, 252B, 250C, 252C that respectively engage the first throughfourth block legs 236B, 238B, 236C, 238C when the first permanent magnetassembly 210B and the electromagnet assembly 212B are retracted. Morespecifically, the electromagnet assembly 212B includes the core 242Bthat defines a core body 244B (outlined by a dashed box) extendingbetween transversely spaced apart first and second core ends 246B, 248B(outlined by respective dashed boxes). First and second core legs 250B,252B (outlined by respective dashed boxes) respectively extend forwardfrom the first and second core ends 246B, 248B, to respectively engagethe first and second block legs 236B, 238B. Third and fourth (further)core legs 250C, 252C (outlined by respective dashed boxes) respectivelyextend aft from the first and second core ends 246B, 248B, torespectively engage the third and fourth block legs 236C, 238C.

The coil winding 254B is wound about the bobbins (see FIGS. 3C, 4B)placed about the core body 244B. When the first permanent magnetassembly 210B and the electromagnet assembly 212B are retracted, thefirst permanent magnet 240B and winding 254B are spaced apart from eachother in a forward-aft direction by a first clearance gap distance G1Ato define a first clearance gap. The second permanent magnet 240C andcoil winding 254B are spaced apart from each other in the forward-aftdirection 208 by a second clearance gap distance G2A to define a secondclearance gap. As illustrated, in the forward-aft direction 208, thefirst and second clearance gaps have different sizes such that the firstclearance gap distance G1A is larger than the second clearance -gapdistance G2A. However, this configuration is not intended on limitingthe scope of the disclosed embodiments. An air gap AG is between thepermanent magnet assembly 210B and the rail 109. As indicated above, theairgap AG tends to be larger for higher speed elevators. Morespecifically, the front-to-back airgap AG may be defined by the distancebetween the teeth 232B, 234B of the permanent magnet assembly 210B andthe rail 109.

As shown in FIG. 10 , in normal operation, the first permanent magnetassembly 210B is magnetically attracted to the electromagnet assembly212B because the core is made of steel. Additionally, return biasingmembers 214, 216 (FIG. 3 ) biasing the electromagnet assembly 212B toretain it within the system housing 202. As indicated, in embodiments,the return biasing members 214, 216 may be return springs, implementsproviding pneumatic or hydraulic pressure, or elastomers or rubbersprings, connecting the electromagnet assembly 212B to the housing 202.Further, the second permanent magnet assembly 210C also acts to retainthe electromagnet assembly 212B within the system housing 202 becausethe core 242B is attracted to it.

As shown in FIG. 11 , when the electromagnet assembly 212B deploys thefirst permanent magnet assembly 210B (also referred to as a triggerstate), current in the core 242B acts to repel the first permanentmagnet assembly 210B, moving it forward to the hoistway rail 109. At thesame time, the current also increases the attraction of theelectromagnet assembly 212B to the second permanent magnet assembly210C. That is, magnetic flux flows out of the core 242B, through thefirst permanent magnet 240B, while flowing into through the secondpermanent magnet 240C.

As shown in FIG. 12 , when the electromagnet assembly 212B is in a resetstate, to retract the first permanent magnet assembly 210B, current inthe electromagnet assembly 212B is reversed. This causes theelectromagnet assembly 212B to simultaneously be attracted to the firstpermanent magnet assembly 210B and be repelled from the second permanentmagnet assembly 210C. That is, the magnetic flux flows out of the core242B, which is revered from the trigger state, through the firstpermanent magnet 240B. At the same time, magnetic flux flows through thesecond permanent magnet 240C.

As shown in FIG. 13 , once the electromagnet assembly 212B contacts thefirst permanent magnet assembly 210B, the first permanent magnetassembly’s 210B attraction to the rail decreases. A spring reset force(F-reset spring) is provided by the return springs 214, 216 (FIG. 3 ) tobias the first permanent magnet assembly 210B and the electromagnetassembly 212B back into the system housing 202 (e.g., FIG. 2 ).

FIG. 14 shows a method of operating a FAM 200B for an elevator governor133 of an elevator system 101. As shown in block 1400, the methodincludes the first permanent magnet assembly 210B of the electronicactuator 200B, being magnetically attracted to the electromagnetassembly 212B of the electronic actuator 200B. As shown in block 1410,the method includes the return springs 214, 216, of the electronicactuator 200B, acting to retain the first permanent magnet assembly 210Bwithin the system housing 202 of the electronic actuator 200B. As shownin block 1420 the method includes the second permanent magnet assembly210C of the electronic actuator 200B, which is configured to bestationary within the system housing 202, acting to retain the firstpermanent magnet assembly 210B within the system housing 202 because theelectromagnet assembly 212B is attracted to it. As shown in block 1430,the method includes energizing the electromagnet assembly 212B to repelthe first permanent magnet assembly 210B, moving it to the rail 109, andincreasing the attraction of the electromagnet assembly 212B to thesecond permanent magnet assembly 210B. In one embodiment, theelectromagnet assembly 212B is normally energized to actively retain thefirst permanent magnet assembly 210B within the system housing 202. Insuch embodiment, the first permanent magnet assembly 210B may bedeenergized (or deenergized state) to thereby push the first permanentmagnet assembly 210B to the rail 109.

As shown in block 1440, the method includes energizing the electromagnetassembly 212B to reverse its polarity, causing the electromagnetassembly 212B to simultaneously be attracted to the first permanentmagnet assembly 210B and be repelled from the second permanent magnetassembly 210C. As shown in block 1450 the method includes theelectromagnet assembly 212B contacting the first permanent magnetassembly 210B. As shown in block 1460 the method includes the returnsprings 214, 216 to bias the two assemblies 210B, 212B, stuck to eachother by magnetism, back into the system housing 202.

The above disclosed embodiments pertain to a FAM 200B that is able totrigger and reset over large airgaps. This is particularly advantageousfor higher speed elevators where larger airgaps are present due to theincreased front-to-back float. This actuation over larger airgaps isenabled by the inclusion of the second permanent magnet assembly 210C,that is stationary. The core 242B, rather than being C-shaped, isH-shaped.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,element components, and/or groups thereof.

Those of skill in the art will appreciate that various exampleembodiments are shown and described herein, each having certain featuresin the particular embodiments, but the present disclosure is not thuslimited. Rather, the present disclosure can be modified to incorporateany number of variations, alterations, substitutions, combinations,sub-combinations, or equivalent arrangements not heretofore described,but which are commensurate with the scope of the present disclosure.Additionally, while various embodiments of the present disclosure havebeen described, it is to be understood that aspects of the presentdisclosure may include only some of the described embodiments.Accordingly, the present disclosure is not to be seen as limited by theforegoing description, but is only limited by the scope of the appendedclaims.

What is claimed is:
 1. An electronic actuator for an elevator safetybrake, comprising: an electromagnet assembly; and a first magnetassembly disposed forward of the electromagnet assembly and configuredfor being deployed to engage, and retracted from engagement with, ahoistway rail, depending on an energized sate of the electromagnetassembly, and a second magnet assembly disposed aft of the electromagnetassembly, wherein the first and second magnet assemblies are configuredwith a reverse polarity relative to each other.
 2. The actuator of claim1, wherein: the first magnet assembly includes: blocks spaced apart fromeach other in a transverse direction, respectively defining blockbodies, and block legs respectively extending aft from the block bodies;and the first magnet is disposed transversely between the block bodies;and the second magnet assembly includes: further blocks spaced apartfrom each other in the transverse direction, respectively definingfurther block bodies, and further block legs respectively extendingforward from the further block bodies; and the second magnet is disposedtransversely between the further block bodies.
 3. The actuator of claim2, wherein: the electromagnet assembly has a core that is H-shaped todefine legs that respectively engage the first through fourth block legswhen the first magnet assembly and the electromagnet assembly areretracted.
 4. The actuator of claim 3, wherein: the core that defines: acore body extending between core ends that are transversely spaced apartfrom each other; core legs respectively extending forward from the coreends, to respectively engage the block legs; further core legsrespectively extending aft from the core ends, to respectively engagethe further block legs; a coil winding is wound about bobbins placedabout the core body; and when the first magnet assembly and theelectromagnet assembly are retracted, the first magnet and the coilwinding are spaced apart from each other in a forward-aft direction by afirst clearance gap distance to define a first clearance gaptherebetween, and the second magnet and the coil winding are spacedapart from each other in the forward-aft direction by a second clearancegap distance to define a second clearance gap therebetween.
 5. Theactuator of claim 1, comprising a system housing that defines a hoistwayrail engagement aperture, wherein: the electromagnet assembly isdisposed within the system housing, spaced apart from the hoistway railengagement aperture; the first magnet assembly is disposed in the systemhousing between the electromagnet assembly and the hoistway railengagement aperture; the second magnet assembly is disposed in thesystem housing so that the electromagnet assembly is between the secondmagnet assembly and the hoistway rail engagement aperture; and thereturn biasing member is disposed between the system housing and theelectromagnet assembly.
 6. A method of operating an electronic actuatorof an elevator safety brake, the method comprising: a first magnetassembly of the electronic actuator, being magnetically attracted to anelectromagnet assembly of the electronic actuator; return biasingmember, of the electronic actuator, acting to retain the first magnetassembly; a second magnet assembly of the electronic actuator acting toretain the first magnet assembly due to magnetic attraction with theelectromagnet assembly; energizing the electromagnet assembly to repelthe first magnet assembly, moving it to the rail, and thereby increasingmagnetic attraction of the electromagnet assembly to the first magnetassembly; energizing the electromagnet assembly to reverse its polarity,causing the electromagnet assembly to simultaneously be attracted to thefirst magnet assembly and be repelled from the second magnet assembly;the electromagnet assembly moving to contact the first magnet assemblyfrom magnetic attraction therebetween; and the return biasing memberbiasing the electromagnet assembly moving to contact the first magnetassembly, stuck to each other by magnetism, back into the systemhousing.
 7. The method of claim 6, wherein: the first magnet assemblyincludes: blocks spaced apart from each other in a transverse direction,respectively defining block bodies, and block legs respectivelyextending aft from the block bodies; and the first magnet is disposedtransversely between the block bodies; and the second magnet assemblyincludes: further blocks spaced apart from each other in the transversedirection, respectively defining further block bodies, and further blocklegs respectively extending forward from the further block bodies; andthe second magnet is disposed transversely between the further blockbodies.
 8. The method of claim 7, wherein: the electromagnet assemblyhas a core that is H-shaped to define legs that respectively engage thefirst through fourth block legs when the first magnet assembly and theelectromagnet assembly are retracted.
 9. The method of claim 8, wherein:the core that defines: a core body extending between core ends that aretransversely spaced apart from each other; core legs respectivelyextending forward from the core ends, to respectively engage the blocklegs; further core legs respectively extending aft from the core ends,to respectively engage the further block legs; a coil winding is woundabout bobbins placed about the core body; and when the first magnetassembly and the electromagnet assembly are retracted, the first magnetand the coil winding are spaced apart from each other in a forward-aftdirection by a first clearance gap distance to define a first clearancegap therebetween, and the second magnet and the coil winding are spacedapart from each other in the forward-aft direction by a second clearancegap distance to define a second clearance gap therebetween.
 10. Themethod of claim 8, wherein the electronic actuator includes a systemhousing that defines a hoistway rail engagement aperture, wherein: theelectromagnet assembly is disposed within the system housing, spacedapart from the hoistway rail engagement aperture; the first magnetassembly is disposed in the system housing between the electromagnetassembly and the hoistway rail engagement aperture; the second magnetassembly is disposed in the system housing so that the electromagnetassembly is between the second magnet assembly and the hoistway railengagement aperture; and the return biasing member is disposed betweenthe system housing and the electromagnet assembly.